One dilemma associated with both medical and surgical oncology is the need to delay delivery of adjuvant therapy such as chemotherapeutic agents or radiation to a patient following cytoreductive or excisional surgery to remove malignant tissue. It is believed that the delay will allow the patient to recover from surgery prior to delivering the adjuvant therapy, and to allow for the healing of anastomoses, resections, fascia and skin to occur without the presence of cytotoxic agents. The consequence of this practice is the potential for any residual cancer cells present at the operative site, or sites distant from the operative site, to reproduce and metastasize. As a result, the intended benefits of the surgery may be compromised. Another dilemma associated with both interventional oncology is the need to deliver neoadjuvant therapy, i.e., chemotherapy or radiation prior to surgery, without causing excessive destruction of tissue or toxicity that may affect the patient during surgery or healing post-operatively. Since neoadjuvant therapy is typically stopped 1-2 weeks prior to surgery, the tumor has a chance to grow, thus potentially compromising the intent and benefit of the therapy itself.
Still yet another dilemma associated with surgical and medical oncology are the effects of both neoadjuvant and adjuvant therapeutic agents on normal tissue. The significant side effects associated with chemotherapy may limit its potential effectiveness and in some cases, cause the patient to decline the therapy in favor of palliative care instead.
Still yet another dilemma facing both medical and surgical oncologists is the matter of “inoperable disease”. In such a circumstance, tumors may have spread to sites distant from the primary tissue and there may be too many tumors to make surgery feasible. Other “inoperable” tissues may be integrated into or surround vital structures such as an aorta, nerve, or vena cava. Tumors of the pancreas also present challenging issues to surgeons because the tumors invade or abut many vital ducts, vessels, and other structures. In some cases the tumor may be very close to the major blood vessels and it may be difficult for the surgeons to determine with a reasonable degree of certainty whether it is safe enough to take out the cancer solely on the basis of a review of scans of the site. This may require the additional step of beginning the operation with a laparoscopic procedure to make sure it is possible to safely remove the cancer before proceeding on to the full surgery. In other cases surgeons may prescribe a course of chemotherapy or chemo-radiotherapy before surgery to try to shrink the cancer to make it operable. Nonetheless, even with these approaches the prognosis for surviving pancreatic cancer is remarkably grim. Pancreatic cancer (PaCa) is the fourth leading cause of cancer-related death in the United States. The median size of pancreatic adenocarcinoma at the time of diagnosis is about 31 mm and has not changed significantly in last three decades despite major advances in imaging technology that can help diagnose increasingly smaller tumors. This is largely because patients are asymptomatic until late in course of pancreatic cancer or have nonspecific symptoms. Increased awareness of pancreatic cancer amongst the clinicians and knowledge of the available imaging modalities and their optimal use in evaluation of patients suspected to have pancreatic cancer can potentially help in diagnosing more early stage tumors. Another major challenge in the management of patients with pancreatic cancer involves reliable determination of resectability. Only about 10% of pancreatic adenocarcinomas are resectable at the time of diagnosis and would potentially benefit from a surgical resection. The final determination of resectability cannot be made until late during surgical resection. Failure to identify an unresectable tumor pre-operatively can result in considerable morbidity and mortality due to an unnecessary surgery.
The ability to successfully treat patients with cancer is dependent upon the ability to locate a tumor via imaging and subsequent treatment by neoadjuvant therapy, surgery, adjuvant therapy, or combinations thereof. In some instances, imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) may detect small tumors that are undetectable by palpation, gross observation or endoscopic visualization. Localization techniques for small or inoperable tissues can be classified into three major types: image-guided surgery; injection of liquid materials through fine needles; and, placement of percutaneous wires.
For example, the use of ultrasonography (US)—guided surgery in lung cancer surgery may be time-consuming in the operating room because the lung parenchyma must be completely deflated for visualization, and this may be impossible in patients with extensive emphysema. In addition, growing nodules are most commonly identified with CT, and it may be difficult to ascertain with certainty that the nodule identified at intraoperative US is the growing nodule seen on the preoperative CT scan. Guidance with use of liquid materials, including methylene blue dye, contrast medium, and radionuclides, has also been evaluated. However, liquids may diffuse away from the nodule such that fixed time intervals between localization and surgical resection are required. There is also a potential risk of systemic embolization if the solutions are inadvertently injected into the pulmonary venous system.
Localizing wires are well-known devices for marking areas, such as tissues, in a tissue mass, frequently breast tissue. When such a tissue is identified with a medical imaging technique, such as radiography or ultrasonography, it is often desirable to position a localizing wire or other type of imaging marker near the tissue to facilitate locating the tissue during later procedures, such as biopsy or surgery. A practitioner can then use the wire as a visual and tactile guide to the tissue rather than solely relying on imaging techniques, which currently provide good 2-D images but not 3-D images. During surgery, surgeons typically prefer a localizing wire to locate the tissue because it leads them straight to the biopsy site. The implantation of a localizing wire requires a needle to be inserted into the tissue mass under guidance from an imaging system. The needle is positioned with its tip at a selected location at or near the tissue. Once the needle is in place, the localizing wire is extended through the needle and out the tip into or adjacent the tissue where the hook on the end of the wire engages the tissue mass. Thereafter, the needle is removed from the tissue mass, and the localizing wire remains in the tissue.
While the known tumor localization systems described above are sufficiently able to direct the surgeon to a target tissue, they are limited to that function and lack the capability of delivering neoadjuvant or neoadjuvant therapy directly to the tumor or adjacent tissue. Furthermore, if the cancer has been present long enough such that some of the cancer is outside of the field of surgical removal, recurrence is inevitable no matter how thorough or complete the surgery. There is a need in this area, and it would be beneficial to cancer patients, for medical devices and methods of treatment that provide for the administration of chemotherapy, radiation, electroporation, or RF energy, etc., which could be enabled at periods of time that most favorably impact the course of the disease, and have the delivery of these agents focused on the tumor or surrounding tissue without having to deliver the agents systemically. It would further aid both patients and clinicians, and advance the standard of care, if rapid and repeated multi-modal treatments of the tumor can be made without the need for subsequent imaging.